SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c07d0ca4268621e8148d281f858fe91123919539dc83df50e7b84cbe2127f19a' 
  AND token = '3T2pbKENng/uPVjeRqNGo8S0AXaThkJ89gs30rFSBkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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