SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '349847f95c9a462d61a7b06614b80ab6ddabdb711e46fa261a1d3804b00ba8ed' 
  AND token = 'MWdrfqGxpyO10MZDz46weFFhss7EzLp6fQlmMV7yTe8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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