SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd8172dedecf4c288e87ebbe0ade57503d81630fa6348a8175eb0edc30da7a2d' 
  AND token = 'A2ZHGOBMVM80UA0Y5o0eqGHvKIdFSXL/5t/pKEyBWH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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