SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b40ffda1839e767f085e2945245a5b09ef8cc0cd93f5a1437163dc694322bcd8' 
  AND token = 'ItzOjcGy3wMUx/MW6A5Sceu3CVEUI57ieBBtpHkFeas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}