SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b79566092c29545c234079322af4a71e832894df81943a2ff3d3c74c34010473' 
  AND token = 'Qeby2jVz6oCFFR9W4kgwMi5ZynRgrhrN6HkNG7DO+nE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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