SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57ddf84a8c44f4ef2dede44890dc4c67bba15403240046df2145812df424e473' 
  AND token = 'vagvg14NYoE5NXMIpgBWysMsViqC1HKNJvgA2wCpsyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

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