SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3c108df89748b607d6241456952645208f7b19a505bba8522ef9fb97393eb3f' 
  AND token = 'fpBtTz/KOGadDntATKCmVm7G89l1ghAf19FE1n2NWVw=' 
  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"
    }
  }
}