SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30b89b768868acaf597f8568ce9c6b55d2cc6deaf71ae14800dba366fedcf332' 
  AND token = 'FW7zvXEfx8+SCtAeaFiTN2CAnTKi8kkeZnL5Z6/rjBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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