SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c178a8d0e5676318255d104cf706c94a4b64fe53a3d4501fd98ecaed90e4ca85' 
  AND token = 'n4/vH7vKmS8nRPV0YvAWGTEwpy/0yh89OhuybUKGhkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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