SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75291d3148b5ff24fff85c660f384a439c41270b8f290816422c65c6a50c67a1' 
  AND token = 'mE9YKRgXFFnOoaXspRl/E9nGpTOBcgbmJ4NUmGSwFxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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