SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19d060ed4409fba220bfca88658b47dd54504a540eeee93bd1faac801c40d44f' 
  AND token = '6dGY8fP2L2KWetB5ywdtRglCEr9qZRw9sPGTFBS4UUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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