SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c137a40f2929ac082c8e15e303172ed9eecf553c7937c7b31b3143337ad62f3' 
  AND token = 'YgNPRpAr66z8kygJyc0WiakCn4unl8cZmd7eWSTX6o4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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