SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7f7183b0da9b0b1be88bafeee86f1614aabfd97450d3367523d7fdf8a3d0532' 
  AND token = 'psAi5c4aAJHVqiQO6c3DfZsoPSnKKaCohGnxbjGLZrc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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