SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '51db7ce0bb4e8c196efc1451366e59d7b3308bafe8076dbbb489fbdd61d69c5e' 
  AND token = 'YlQKywgozI5qbhj7/wZzbbUoHV3vG7eYDGfgDSmZPWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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