SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e109c0a2a177ac33926907908620e31dd11f3a3fd245bce3e978b567ffc1d25' 
  AND token = 'd9CVPxK1BeBio7kZfNYxBNzYPQ2hWJMmhHXOT1EiK/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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