SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2853bb86f53af87e4ba43bd627e250b1708d139d81f9e901d587edc5042d98b' 
  AND token = 'Vq4V1waevNsvaf15vnxiIH00JE5n9KTJoVY02K2koPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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