SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e478bf32cd194a5f8daffdfa96a1099ee40c3affdc200b348263957a898cd318' 
  AND token = 'kdrNKRAy5GE1zsW1t2B+gexCGfgTupTu+GHORcxCQrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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