SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b5ea516a74f73550712be37b024f33b2853975bd7c5ea545c42b473acaf7d94' 
  AND token = 'kB1vx9n9ebCTDpUzAL5GvQZBCY/6htla7kvXuskyZ/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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