SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd2d0e189b28fd255167c8cf70d9a1cd1c481a5858ba3e8ffbbbe9d87a241db4' 
  AND token = 'uNTlowyqcdhnhq2RWyjqzZ3r5Amzx1rK9FaAKw/7FFA=' 
  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"
    }
  }
}