SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e83e73ca94cb4b3dec4d6867cc107b675f3e58fa77a319f6e446b6cdfc967796' 
  AND token = 'M6T7iM+KnVQn6vU2uV5Lh1rEh5nMyQ5ns60DoME23AU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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