SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cb9a988c1a87c5502fb7e3d61d21bab9cab8eb9edf71949695fcc3fd4b37318' 
  AND token = 'VP+394ShZTRQ605t2gEdzTWQQYqbvSltlxlLiQ2ymiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}