SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd639cf24970c7bfa43cf4fffe35ff981fc891eff09331457315e8d626bb0441e' 
  AND token = '4dcnmxsxgEdrlrhHE3jC4hojoYaKNfaePwHRBEtlEU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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