SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '764fccbbc59d9ab79d3e4883ef09de9fa1f8ffec07c1e35a51f22978ef72bb98' 
  AND token = 'W3fdoIF0YVtH0v3vzprK4bRLvENbzKnnucetNzOB65c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}