SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68ce51ffe5f83a4dedaaf070aac1625d64bb60a46bd7c65eafa38b10a1f20cf7' 
  AND token = 'NzL6mWXMCGTy+J4Qe8WeXWuNSVeztbQwRru0fp2oaB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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