SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '78f444017b665d78b32dc54ffe0829c1cb531730d20c6a2238f23c7a9fc308cc' 
  AND token = '63+NrbWKVwcmkb2l+KGf90kAKPHUkq5K1UxljZ4+8QQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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