SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '858b98062b8b0aa7a8f032c76b2c480ed372eed65e86c7501f5aa39f0336d233' 
  AND token = '5qq9xebtmgOW+/GjIQgtV51THK8EDhwv4X05IaozLhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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