SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90cfbe210d5e884a216134321edb4b9d379004e622f6d30524b0cc87e7adfa54' 
  AND token = 'vdojqnpy+uVFXE71hFgfiraNilVGlUgL9rZT/sV6R7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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