SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f969faef0db6caa4b9f4586b2a23667331b0eb86a56b8d4a795386ddfd7a99f7' 
  AND token = 'PkSF1iz54zuLBOBsLKd2kw51cTZBuEeKZbBdqcHyYq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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