SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a61e762969187388814c3a6df6d14ef44ce5bc75f4ecb234eb20a9d9639f05b' 
  AND token = 'aCwgGrW4BmAfZeSTb5BVOilOh9M/ETpjbXvoxvVNdpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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