SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '752d74e614089fe51efeffcb985454e485f7d471359ce0b99983ef400e6a540f' 
  AND token = 'cgVUm7fuXTvQPaZleKDmGhRIUzV4O3W+ffJxDt/RjiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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