SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b2466bc8ac23a23573ffb4199014dfd58150e614138d1212721c5dcf0cc7d647' 
  AND token = 'xIV+46HYY3EOjHCnjbge5//W8nHEjxAwCb1Bq3wsz60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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