SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f6cd63c9189545c3b3e2df77873155ac7119a27a1728e428dd83e39f5551c44' 
  AND token = 'xYZ10BSjeOzue87Vnp3RFLqvXj9qDBDZP1jZP7Uh0y4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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