SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f947f1bc540161b54cc966b4d141e095522eec5efd0e6589989fbf558f2e79bd' 
  AND token = 'YR5jYFktzsCG5G2I/P3Cn7VHN0FH5gLUeqAPLpjsJgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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