SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c208c72c1d8e368b260d854665ffd7bf79d2c353af26f12df36fe802f9ba735e' 
  AND token = 'NBifMGMQguFSfG01ND1vcbUgsGWS0M7OnIAXcOhmbi8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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