SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41e2cb78d0b42ef1f419b0caf85700c246d3e75b7734c32c7a59fb59805b2503' 
  AND token = 'VZIydLGYRAaufRh7dDWc5giLLph6zCUtfyKjvjYLYvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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