SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b6b4e71f282398cb53287858455f2a6a2746ea886b2f6c38f7f1690077deb0f9' 
  AND token = 'b3YmlfhJecWkmtVIFXN7x0+Lm3GdJFHIW2I5WVuK7Lc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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