SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38fe6670fb189ec4738d3426083ad350cf0ddbd52ef503c12cb01f662e076bba' 
  AND token = 'uEBtjhks7baf/ErZUYpiPXQytzWNzDVdFHA0IhxKefY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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