SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0291122c8c390be2bacaf10fe1d2350c4712006e429374d3fd60815635816ed4' 
  AND token = 'Ye8jOYsmNkO4MgjCiTh+Pb7wPJqJrT6JPZBPhCbInQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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