SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cc4a3df438be445c0421d99569d4adddcbabc947fee98d50658cacbebba8e29' 
  AND token = 'hXNtKTak5VgtA2H1dbq9k+1I5tt+5Pj4CBJPNYZAqJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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