SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd4f9ee3c249a305ba12a91acb5c750a5492278444d4580371f6740f7340644cb' 
  AND token = 'e821vQYtbGWLzQwCS8TqBCdNHaBRZLrWcKGLJGMCIMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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