SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81709142ede75d3d72609f2981495d3f2fb1e9c85b06d695d33d07fd23fc29ea' 
  AND token = 'EVNE6XbpfFyHkoDrSPu8/5PQnaG8piAyr0tXc+6yq2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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