SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8be8c27e93e2de0a9801764f82bbc9059a8aabfa9a28bc3caa6b5082f0a64010' 
  AND token = '+Mmd2CQBFFAAXNSRaWJ3oipPj0YDqJNpdNiBnBjyPak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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