SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15bb2a8696dbc2a62c598b9fdd41664a7565a38dff409fc5862110ffa9fbe158' 
  AND token = 'VYEdkYpmcUx+Y+X6XrGvjkIFqdew/jKn2bZkADWD2kg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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