SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77deffa0c5aab681d70c30506733c0810251eb13914912e6521c1cff30790ca4' 
  AND token = 'ESgFwAw+Mmpd058PTLxUBD7dtRpP+tMDEq58PBXvCHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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