SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd822e086bff8e7804f3102a1398549c4d47b1f099b22193baa7363f518333b39' 
  AND token = 'PFyH+c5EGFbIzjMbhsuq5r1rkfPzSigftzbNbHpoKOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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