SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6ebfb3e3a7e817a75fb13b69145d8734a746c7513fa1a12c6c4448be9bb3b9e8' 
  AND token = 'ULw5cwgL91HyJngnwX6vX1/bLutOJMGL5cigmcmie48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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