SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bcd2986a25c9a750082a31e3a3fdf6370a05de9e580f2ad2044384bd12b389b' 
  AND token = 'dSAowhUP1K1XqZM7GFFWn5ZGrAQt0y+1x8brwPirHrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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