SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '583f64fa15db6bdf25078a585d63c156c3cea15eddb46bee93ab707e3a3bc380' 
  AND token = 'ZjMiV1+hNuwEHGS2q7VWMy/4UgjyMez4gHfpBvmGHr0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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