SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e35feb7c09637ce0cd3e40f9f912ab3817e679d5f1017ef95854aba2bb59bbf' 
  AND token = '6FhS/CHJXzcZEjdeV2WlIEuLqyZihBwQTFltVrBg+8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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