SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '419cfaefb562d39ffea4d049aad4ddda4cf69df3414fed6ade5c9231b1a8ad78' 
  AND token = '9PqdDdnOGoJJIGTtR9JV1bsCRu74pzax9FkthPfzPCU=' 
  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"
    }
  }
}