SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6936e79292b4db8ba6e11dd62dc0a2c2d48b33a9c0242746df733c92fa5ffe35' 
  AND token = 'M8z2PSGAVyEGHqjD97LMVRu47LR3IUzUKi6qHzHvphQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}