SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9633d181385f29ddc85886e9723b2cdbd3d936db8238c1f53f6edd6571f5b536' 
  AND token = 'kjjco2qiriUCHgm/KFvEAQZEqH5znx3agXfoZZtXV60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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