SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '440de1c58980470c9782cc58265ba7c7db7082359fe4274f55e3f66945567206' 
  AND token = 'eUYkD1tLezTOebEeTKsLukMxiAOTRuCrFOZdEuyyRp4=' 
  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"
    }
  }
}