SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f37e7472da46091a2c6840274f035d033506495b205bf0f560ef0d7a1228cddf' 
  AND token = 'EaX7LWpeuEufbqGrEMPluTOa/gStvkUtnYnLJVBgPmU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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