SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6974fb6dad9fafe053bff815d2ee556622e81306b514d86ee6d5a8f80a34676' 
  AND token = 'q80QBcClL1UMoGe5ErcbmJxbAkvxYbqRBHCBgzkauBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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