SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '245c1c5091df05ceaf81204fa91e374270f2ea8d57d71c8bb8f398ab5e203a23' 
  AND token = '8ISZnSDOy/RU52MkuV6EswPKQ8IpCUNBfeYcGdVIZwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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