SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f90aa87fdd1469ff344e07745463bd2ea2a8dedaf5ce910c1fc3ed2abdd6174c' 
  AND token = 'WYGO7NZULXs3GVS7uF5tqYrZLSylVVbU7IO/PA3stmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}