SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b85658fcd7c7db0917f9369399f0a64b96e52fc426c8e9a89dca296007b4317b' 
  AND token = 'vn/fMKhp+RWYjOJozQWa2REhJ8BZ4by/WI9oy3uLaJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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