SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd12ddfea4cc7500065dd150695ba8578d5b2e3fbdd735b720f6f325606b70958' 
  AND token = 'sMheLD7BOHcUv8vLUzmIHzJfy7J6XCah0avrOZyIR0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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