SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '097a9cee18853666b517a3f76cccefa73b3ce80053236c0de7df0425302582a0' 
  AND token = '8xERRxDoYGiJZ20IbUO/JrXiljbOpEuoF7Rr+HlVRbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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