SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f66ff3d6ff2db2e363d16965e14ed7c4d961c38cb4c78f5c4ff870c475c0c5d' 
  AND token = 'VYpOl9H3wUKk8+iqCt2cpMc6U7ZSUWXqlAcEdgGAcEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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