SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '618085a275284258a756007d9b8bb272451f59f2966cddd04b35a592b0be5d9c' 
  AND token = 'S08MZJPYSKaiEnvCTPft57KvBulFz0tdGqREotWBHyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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