SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09b9981b556192305e34001b4b4352e39267b158724993e660a545a60b1fbbf1' 
  AND token = 'EoTRq9S7sgFQGCimQQxLH8jsmlZNVfHulghYMXwdTK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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