SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '223364153af4e2e20ee83db5fa96768c5e0f759fdc1f5aafa9b5b94d0fd52912' 
  AND token = '8QkDIKaE1S381MIF0ANZcbwAXZooXe7q0qBFWtI/yy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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