SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffd3efa132588c92606b0ad019244c436c9335ecf13664520ac0e3a44b24a5d5' 
  AND token = 'qNL5s6lu4YYLVcT/fCOMj/0o3In04EWDyBzCIhtRZGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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