SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3defa11b5e3dbccf5626a2a4ccd872b5e1cf1c635687b2cfd9f3dca15c6822e1' 
  AND token = 'nDrf0rJZ67u1vdr3OmXexR9lUmfyqsXIgd/ibfueoLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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