SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20cc3dfe04b4288d694aa7f085b32f74da8c6322dfc5c4fcdebdb47772131515' 
  AND token = 'mtQ/EvfFSu8M1EeoLfLQ9cbvmAUs3zBTfo3wAFdbxjo=' 
  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"
    }
  }
}