SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '567a9cba57c742328bc584894aded7496b177053e44ed040838467e8fecb1c24' 
  AND token = 'hUqxIy83T+T70nGZ0dZRuwmm4Rin3oI/otAakQjaBWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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