SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2166a6c89b449695cbe084180a11013be5873c7011871035f91976b9a74e41d9' 
  AND token = 'kGCgwiBJ6ZKo94J0UueQiAGrwEUY3p7BEfXZb5JbrYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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