SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'cb742873b1a0f8e69b828d3c8fc3658d5678e5b38a7a40a5be99599656761c7a' 
  AND token = 'JAT7FqUPWrXg+L4SI1OhXCGHpkwgJwHx3nVV7IftgeI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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