SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cdb47f6a3a78b243658f460585e511c6a02c6470d51da3caa57d067d9c46002' 
  AND token = 'RB7vHJHWSt6s+9oxpXw8c/r0gV+hSshRKnLbgSzlOmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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