SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4391583d47d3d254cc141bd128340aedeaf421373ad88fe241801cabe36d17d' 
  AND token = 'cua33Ptdg99PGCkAwfx2WKk1lL3rCA7nQj6eimpbnN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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